Unique entries with security assist update page

I've got an issue where I have used security assist to create a registration/log in section and I have declared a field (fld_callsign) to be unique, but on the user update page, if the user changes their phone number and nothing else, the unique field prevents the page from submitting because the users unique 'callsign' already exists in the DB.

How do I get around this? I tried to sort it in the SA wizard before it created the pages, but whenever I made a change to the update user page, it also changed the registration page. I tried to make it just text rather than a text field, but as I say, If I changed one page in the wizard, the other changed too.